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US 4,712,089 AGranted
All-optical A/D conversion using integrated nonlinear guided wave optical circuitry
AssigneeBattelle Memorial Institute
InventorCarl M. Verber
Life of this patent
Estimating the term…
Abstract
Methods and apparatus for all-optical analog to digital conversion. An analog optical input signal is directed along a path comprising a series of level sensing means for determining whether its intensity is above or below a threshold value. The optical signals from successive level sensing means are directed in pairs to optical exclusive-or gates to provide a digital optical signal to at least one of a plurality of individual optical output means according to a designated digital coding system whereby the optical digital indication corresponds to the sensed level of intensity of the analog optical input signal. Apparatus comprising channel waveguides and integrated optical devices provide economical systems for high-speed computation and other uses.
Claims16
A method for receiving an analog optical input signal and for providing a digital optical output signal indicative of the intensity of the analog input signal, comprising
- directing the analog optical input signal along a path comprising a series of level sensing means for determining whether the intensity of the analog input signal is above a predetermined threshold and for providing a first binary optical threshold signal of a first predetermined intensity within a first predetermined range of intensities when the intensity of the analog signal is above the threshold, and for providing a second binary optical threshold signal of a second predetermined intensity within a second predetermined range of intensities substantially separated from the first range when the intensity of the analog input signal is not above the threshold;
- the first level sensing means providing a signal indicating whether the intensity of the input signal is greater than a first (lowest) designated intensity, the second level sensing means providing a signal indicating whether the intensity of the input signal is greater than a second (next to the lowest) designated intensity, the third level sensing means providing a signal indicating whether the intensity of the input signal is greater than a third (next higher, ie next to the next lowest) designated intensity, the fourth level sensing means providing a signal indicating whether the intensity of the input signal is greater than a fourth (next higher) designated intensity, and so on to the last level sensing means providing a signal indicating whether the intensity of the input signal is greater than a last (highest) designated intensity;
- directing a predetermined portion of the threshold signals from the first and second level sensing means to first exclusive-or gate (XOR) means, directing a predetermined portion of the threshold signals from the second and third level sensing means to second XOR means, directing a predetermined portion of the threshold signals from the third and fourth level sensing means to third XOR means, and so on, directing a predetermined portion of the threshold signals from the next-to-last and last level sensing means to a last XOR means (in number one less than that of the last level sensing means);
- each XOR means comprising means for providing a first binary optical signal (indicating inequality) of a third predetermined intensity within a third predetermined range of intensities when one of the threshold signals directed to it has the first predetermined intensity and the other threshold signal directed to it has the second predetermined intensity, and for providing a second binary optical signal (indicating equality) of a fourth predetermined intensity within a fourth predetermined range of intensities substantially separated from the third range when both of the threshold signals directed to it have the first predetermined intensity and when both of the threshold signals directed to it have the second predetermined intensity;
- and
- directing the digital optical signal from each XOR means to at least one of a plurality of individual optical output means according to a designated digital coding system, whereby each available combination of signals in the plurality of individual output means provides a digital indication of the specific range of optical intensities within which is the intensity of the analog optical input signal.
3 more elements
Apparatus for receiving an analog optical input signal and for providing a digital optical output signal indicative of the intensity of the analog input signal, comprising
- means for directing the analog optical input signal along a path comprising a series of level sensing means for determining whether the intensity of the analog input signal is above a predetermined threshold and for providing a first binary optical threshold signal of a first predetermined intensity within a first predetermined range of intensities when the intensity of the analog signal is above the threshold, and for providing a second binary optical threshold signal of a second predetermined intensity within a second predetermined range of intensities substantially separated from the first range when the intensity of the analog input signal is not above the threshold;
- the first level sensing means providing a signal indicating whether the intensity of the input signal is greater than a first (lowest) designated intensity, the second level sensing means providing a signal indicating whether the intensity of the input signal is greater than a second (next to the lowest) designated intensity, the third level sensing means providing a signal indicating whether the intensity of the input signal is greater than a third (next higher, ie next to the next lowest) designated intensity, the fourth level sensing means providing a signal indicating whether the intensity of the input signal is greater than a fourth (next higher) designated intensity, and so on to the last level sensing means providing a signal indicating whether the intensity of the input signal is greater than a last (highest) designated intensity;
- means for directing a predetermined portion of the threshold signals from the first and second level sensing means to first exclusive-or gate (XOR) means, directing a predetermined portion of the threshold signals from the second and third level sensing means to second XOR means, directing a predetermined portion of the threshold signals from the third and fourth level sensing means to third XOR means, and so on, directing a predetermined portion of the threshold signals from the next-to-last and last level sensing means to a last XOR means (in number one less than that of the last level sensing means);
- each XOR means comprising means for providing a first binary optical signal (indicating inequality) of a third predetermined intensity within a third predetermined range of intensities when one of the threshold signals directed to it has the first predetermined intensity and the other threshold signal directed to it has the second predetermined intensity, and for providing a second binary optical signal (indicating equality) of a fourth predetermined intensity within a fourth predetermined range of intensities substantially separated from the third range when both of the threshold signals directed to it have the first predetermined intensity and when both of the threshold signals directed to it have the second predetermined intensity;
- and
- means for directing the digital optical signal from each XOR means to at least one of a plurality of individual optical output means according to a designated digital coding system, whereby each available combination of signals in the plurality of individual output means provides a digital indication of the specific range of optical intensities within which is the intensity of the analog optical input signal.
3 more elements
Dependencies are inferred from the claim text.